I think there are different types. Some people go off about some pretty phony stuff, and I'm sure you'll all agree. Then again, don't you think there are at least some issues happening that are serious and some of the people sounding the alarms are reasonable at heart?
When the alarmism is "phony" I think people are doing it out of a sense of insecurity. When it's valid, I think the people are at least frustrated because too few people are listening or engaged.
Takes a little of every kind to make the world go round.
They're narcissists with weak constitutions. Too weak to survive, so they have to whinge and blow things out of proportion to feel big.
natural born **** disturbers is my guess